编写一个完整的程序，从用户那里读取 3 个数字，并计算和显示仅正整数的乘积

Question

This is what I've tried so far

// Calculate the product of three integers 
#include <iostream> // allows program to perform input and output

using namespace std;

// function main begins program execution 
int main()
{
    int x; // first integer to multiply 
    int y; // second integer to multiply 
    int z; // third integer to multiply 
    int result; // the product of the three integers 
    cout << "Enter three integers: "; // prompt user for data 
    cin >> x >> y >> z; 
    result = x * y * z; 
}

what can i do to solve this question?

Answer 1

EDIT: If you do not need it to loop use a if instead of a while.

Looks like you need to study some conditional statements try:

result = x*y*z;
while(result < 0){
   cout << "Enter three integers: "; // prompt user for data 
   cin >> x >> y >> z; 
}
cout << result << endl;

Should work fine...

Answer 2

I would suggest using a condition to check the number at the input itself:

#include <iostream>

int main() {
    int inum1 = 0;
    std::cin >> inum1;
    if (inum1 < 0) { inum1 = 1; }
    int inum2 = 0;
    std::cin >> inum2;
    if (inum2 < 0) { inum2 = 1; }
    int inum3 = 0;
    std::cin >> inum3;
    if (inum3 < 0) { inum3 = 1; }
    std::cout << inum1*inum2*inum3 << "\n";
    return 0;
}

Notice that in my example I have used std::cout and std::cin instead of using namespace std

use of using namespace std is fine if you're a beginner or the program is small, but is discouraged for large programs:)

If you find typing std:: tedious, you can instead include the following statements:

using std::cin;
using std::cout;

---

Also, printf and scanf is usually preferred over cin and cout for fast I/O.